Rotary kiln



J. ANDREWS Oct. 27, 1931.

ROTARY K I LN Filed May 24, 1928 IN VEN TOR.'

M A TTORNEY eww J. ANDREWS ROTARY KILN Oct. 27, 1931.

Filed May 24, 1928 2 Sheets-Sheet 2 IN V EN TOR. J nd/'6W fwfb M355 ATTORNEY Patented ocafz, `i931` `L fi r1,828,727` i JoHN ANDREWS, or oaKLANnjoAnIroRNIAL i i [ROTARY`K1LN Y y i l' ,application mea may 24, 192s. serial no; 280,326. i

rotary furnaces for reducing ores, more par- 'ing a'partof the feedbar'g-' v yticularly, in vthose employed in lthe'treatment Figure 'is a planylewof' furnace. 'fl of mercuryfbearing o'res, such v as Cirmabar. Figurefiisadetail View of the-feed chute,

`This` invention relates yto improvements in' Figure is a detail perspectiveiyiew, shovv- Y' i' M5 The furnaces generally employed 'for this` being e' Perspective 'SeCeIl'elVeW 011 thellei'igg purpose areconstructedon a large Scale and 4 4: of-Figl. Y are permanently installed forv long continuy ous operation. For thefprofitalole installa- ,lng ein@ @fthe 'feed br-fel' II'IQVIlg tion ,andl operation of such a permanent, furmaterial inthe feed spout.

` 10 nace, it is'necessaryfto have readily yavailable Refeflllg '50 the. drawings lfdetal 'fdsi'ico a large supply 'of ore for .the long continued lgetes the 'eylnhcel ulneee :formed 'of operation of the furnace. In some localities eher@ lbuu eeet'lele 6 heVf-llg efngee 71H5 cinnabar is found deposited in small pockets the 'ends 111 abllttlng, felftlon ,and Seemed andwidelyfdistributed over territory Where 'together by lOOlCS.` To' faclllatefthe Seem? 'Y 15 transportation is difficult. In rsuch a locality, bling 0f the SleetOIlVSa-he Conteetngfaees .0.f'l`65 l 20 W0uld' render the :project unprofitalole. Also, .Y

.25 Vis thee-'provision of Va rotary` furnace Ofa of sponding parts,

. the installation of apermanent furnace would: the?? H enged edS/.fll'e machlfledato .P'OVde Y. Y be impractical,for the closely adjacent tore, A

would Sonberexhausted-and the diculty nal 'axis of thesectlonsk. This uniformity theltransportation of thermore remote ore l l the ltransportation'of.the massivestructural fllcllle"Seleetlonie'fttmg ami@ tghtQlt' 'l units ofwhich thepermanentfurnace.is'ordi- @s afsmld 'Should theebe. lfegulanty fm narily constructed would be iinpractical.Y @ti-1e. .endraesfof theectloils@.gsketfs pim .One of theObjects of the instant inventQn .'be-'mterpoged toprqvlde a tight Joint' Whlle i y Y .y posediof three sections itisto.be'understood knock down character, so constructed 1n units thd-t the number 'of' Sefctonsmay Ybev Varied Figure' 5 is a detail perspectiye'view, shofvv'- y U rflat contacting faces normaltothelongitudi-y Y.

in theends of thevsections permits vthem to- .l Y i 'the cylindrical..furnace shovvnjas'rb'eing com-kv 75 L thatitcanbe readily transported over rough to ,met different requirement@ The?? uhm Y y t Yfunryveaslly assmbl'd, Operative-rela" larfsections arequite short, as v'croinpzared" with @1011 nd'ailSQ feadlly fdlsmllnted fer trans" vthose,employed'in" apermanentplanuso thatTIA portatlon VVto aidlferent'locahty for mstalla theweifght ofpa' sectionjs 'not'toegreat toibe `tion there. By employing such'afurnace, i readily tmsported Widelydistributed'ores in small quantities cany The furnace yis;mounted so as :to beslightly he treatedon'y a remunerati'vebasis- It l also deClDeCl YJGOWM. ijS.V delivery end 'Setht they Y has for its object ,certainv improvements in material beingltreated-vvill tend to travel by' '35; l Itlledetails of construction to render `the fur- QI'WY heugh the 'retort-f It .momted. nace eiiicient in its purpose, tofwhich particu' QI rotl-mn ,on th@ Tous 9 'belfllg @gunst Vlar reference is made furtheron.V` i i. the'gpemlghemeof ith? 10mg@ angesajhse The inventionfconsists inthe novel con` PmalphertesV bemgalso machined toy'pmvlde `struction, combination and arrangement of 1 d b db th '1 Y i h i fter y'described Jointefdfoutfin me 30mn@ Q on @Wings Calme 'e plv" parts ere na l larsl() mounted on suitablefoundations. @n f -a smooth bearing Afor thel rolls'. kvThe rolls 9 96 accompanying drawings.

. .A -Qinountedtlie loevelgear'11..adjacenttlieflangeffgA A45 111th@ acompanylng-drwmss, 111 -Whlch thereof, thetouspassingtumughsuie adja 5 'Simhl'i'eference Characters designate' Coffe-2' cent flanges also extendingthrouglrthegear Figure v1 is a longitudinal Sectional 'ifiw #meshes the bevel fgeap' fiaonfanf@natiche i l `25 Y 'At the lower or discharge end of the furlovs7 spiral flange 23 `andthe direction ofV rotation of the furnace is such that the flange acts as a Worm that tends to move the .ma-4

terial toward the discharge end Aof the furnace. Also, as the retort rotates the spiral 'flange cascades thematerial in the furnace.'

' That is, fthe flange .on the ascending' side o-f the furnace lifts the material from the lower side and asA fthefflange Vtravels upward the vmaterialis graduallydropped and showers Vacross the interior of the furnace.Y This treatment ofthe material separates the particle's so that they are Vindividually exposed to the action of thev gases flowing through ,the furnace.

nacejs a low 'pressure burner 24 for fluid hydrocarbon, positioned to direct the flame into y@the furnace andtowvard'the cascading ore .which serves as insulation'means and protection for the Wall of the retort. From thisg it will readily be` seenrthat the maximum of Vefciericy of the fuel consumedV Will be {paf-fed t0 the burner 24.

l The vburner is mountedthrough a sheet 'steelhousing26-A, which extends .fr 'om'the end ofthe-housing'26, hereinafter referred to, tothetip ofthe discharge pit. .Surrounding `and enclosing discharge .end of the. furnace lis Yprovided the Vcontinuous housing 26 ,and 2 6---Av to retain the heat'imupper ormaterial receiving end the furnace opens vinto the vdust chamber 2'?,V

ivhich is off large volumetric capacity .and is I ,prgvided Withrommunicative means to dedensers, after the dust hasbeen precipitated lpf tube 29, provided the spout 58,'

iverthe vaportoV the usual series of con- ,to the bottom ofthe dust chamber. Mounted .directly behind the rdust *chamber and in di- .andfeeding device to receive'the material to be tr e a 1ted. Leading from the lowerend ofr ,the hopper, through the dust chamber, isv the tubelidemptying'into the upper end of the retort. Between the hopper 28 and the end fopen on lits-upper sidegto permitready inspection should congestion voccur in thetube Y through "the tube vand lspout'isfthe feed-bar 30,rectavngular in cross- ;-jarea and with its corners 'notched, as at 31,toprovide edges to engage .the material tomove the latter along the spoutand tube 165 .das the bar .srecprocated therein. The feed thewloiver end lof the. furnace by rect `line .with theY furnace is the hopper 28 by the burner.

bar is mounted in the guide rods 32 (F ig. 1l)

, eatending across the spout and the ends of said guide rods run free under guide plates 59 providedron both sides of the spout 58,

for the purpose of preventing the feed bar 30 H from rising to the top of the feed tube 29, and

to permit an even movement of the material through the spout and tube. The upper endl of the feed bar is hinged to one end of the Walking beam 33 pivoted to the bracket 34.

Theother end of the Walking beam is connected by the rod 35 with the gear 15 so that vi-'otation of the latter, through the interven- `mg mechanism, imparts a reciprocative movement to the feed bar 30.

l/Vhile this method of feedingis constant and will deliver ya `sufficient amount of ore into the furnace at all times, there isno positive 'amount'deliveredin one given stroke,

thereby avoiding all danger of am ming a.nd :1,:

breakage. AThe conduitfformed by the spout 58 and the tube 29-is ofconsiderable crossarea andV is of large carrying capacity. lhe

conduit is slightly declined from the horizontal so that the movement of the material therein is slow, as eected by gravity. Also, the forward movement of the lmaterialinthe conduit is but slightly augmented bythe reciprocation of the notched vfeed-bar-SO, which acts more to preventthematerial from packving than toaccelera-te themovement. ".As a

result of this slow rmovement of thermateriahthe conduit remains filled and the lopening through the conduit to the exterior of thefdust chamber is sealed s o that, gases cannot escape" therethrough. 'While the .iovement ofmaterial in the conduit is slow,

yet the large bulk` of the material so moved insuresthat the required amount-be fed to theretort. Y s

' The operation of the apparatus is as foli lows: The parts'havingbeen assembled at a locality with a supply of ore atfhand andthe furnace erected, the Ifuel .at Athe:burner 211 is ignited to project theflame into the lower or discharge yend of the rotary furnace 5.- The .products of combustion entering the retort p ass through the VA same to-the vdust chamber 27. This causes a strong draft through the furnaceand the Aa-ir enteringthe lower end of the same' is heated as itpasses` over the' flame projected linto the furnace The products of combustion, passing from the large volumetric Vcapacity of v.the vdust chamber, the cold material` entering through the conduit will have but little chilling efy fect on the products o fcombustion yin the dust chamber and the hightem-peratnre Will be maintained therein; Although there is,-

considerable bulk in the material passing through the conduit, yet the extensiveheatexchange surface of the conduit and the slow travel of the material therethrough. insure a thorough preheating of the material be-A fore it passes intothe rotary furnace. v o

vThe material to b-e treat d 's fed into the vhopper 28 by any suitable means (not shown). The motor having been started, the feed bar 30 reciprocating in the spout 58 and the tube 29, forces the material downward through the tube to be fed gradually into the upper end of the rotatingfurnace 5. The tube 29- A has considerable l-ength so that the material filling the same closes the passage theref' propel the material toward the lower end of t the furnace, the latter beingrotated in the direction required for the purpose. As the furnace rotates the fiange on the upward moving side of same picks up the material and cascades it across the interior of the furfor yfeeding the material being treated through the furnace as the latteris rotated,

said flange also operating to cascade the ma#y terial Within thev furnace, means for introducing heatedgases into the delivery end of the furnace, a dust chamber of large volumetric capacity communicating with the material receiving end of the'fuinace,a feed spout,`

and tube ofjlargey cross-area extending through the dust lchamber tol empty into the material receiving end of the furnace, said conduit having extensive heat-exchangesur.-

face within the. dust chamber and means for` slowlyy propelling the material through the feed spout and tube, the slow` r movement of the material through the feed spout and tube tending to fill the same tol close the opening.

therethrough to the exterior of the dust chamber, and ,saidv slow movement of the material and theV extensive heat-exchange surface of the vconduit operating` to' preheatvv the mate-` rial within the dust chamberV before the ina terial is discharged into the cylindricalfur'-l JOHNV ANDREWS: l

nace. In this way the material is so agitated y and distributed that the individual particles are exposed on all sides tothe reducing action of the vheated gases iiowing throughthe fur,- iiace. c v During the reducing operation, the interior of the furnace, particularly the lower part thereof, ismaintained at a temperature con.

siderably above that at which cinnabar dey composes and mercury-vaporizes. 1 Subjected to this temperature in passingthrough the furnace, the ore is'completely disintegrated and the mercury being volatilized, the draft through the furnace carries the gases into the dust chamber 427, where the dust is precipitated and removed' to the bottom of the chamber. The mercurial vapor is conducted from the dust chamber through the exit pipe 57 to the condensing system. f

The spent ore discharges from the lower end of the furnace into the pit 25. In its passage through thefurnace the ore collects along the lower side thereof.v At the .discharge end of the furnace the burner directs the flame against the ore bed collected in the lower side of the furnace to protect'thewall to some eXtent against the 'direct actionof the flame and also to subjectthe remaining refractory ore to the highest temperaturerof the furnace. Y y J What lI claim is:

In an apparatus for treating ores, the comf bination of a cylindrical furnace, means for rotating the furnace, said furnace having av spiral flange on its inner face to form a worm 

